In Squad Defense, you are in charge of a top-level special forces unit that is under constant attack by the enemy.
When all three of your special skills are fully filled, you can use them. To move forward in the game, you have to survive waves of zombie attacks at each level. Keep an eye on your resources because you need them to improve your soldiers and make them better at fighting enemies that never stop.
Make sure that you divide your resources evenly between making new troops and improving the ones you already have. Don't forget to use your skills when they're ready; they can save you from defeat. Pay close attention to the enemy; knowing how they act will help you come up with a good plan.
Have fun and good luck!